The Common Gateway Interface (CGI) is a simple interface for running external programs, software or gateways under an information server in a platform-independent manner. Currently, the supported information servers are HTTP servers. The interface has been in use by the World-Wide Web since 1993. This specification defines the 'current practice' parameters of the 'CGI/1.1' interface developed and documented at the U.S. National Centre for Supercomputing Applications. This document also defines the use of the CGI/1.1 interface on UNIX(R) and other, similar systems.